Carbureter



J. W. JOHNSON,

GABBURETER.

\PPLICATION FILED FEB. 9. 1920.

PatentedSept. 13, 1921..

2 SHEETS-SHEET 1.

v m m J y J. W. JOHNSON.

CARBURETER.

APPLICATION FILED FEB. 9, 1920.

1,390,790. a ept.13, 1921'.

' 2 SHEETS-SHEET 2.

JACK W. JOHNSON, OF WINNETKA, ILLINOIS.

I CARBURETER.

Specification of Letters Patent. Patented Sept. 13, 1921.

Application filed February 9, 1920. Serial No. 857,272.

To all whom it may concern Be it known that I, JACK W. JOHNSON, a citizen of the United States, residin at Winnetka, in the county of Cook and tate of Illinois, have invented certain new and useful Improvements in Carbureters, of which the following is a description.

My invention belongs to the general class of carbureters used in connection with internal combustion engines, and has for its object a device of the class described, effectlve in' its operation, economical and durable in construction and use, and simple and readily understood in its adjustment under the varying conditions met with in use.

To this end my invention consists in the novel construction, arrangement, and combination of parts shown and described, and more particularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like. or corresponding parts,

vFigure 1 represents a vertical sectional View through my improved carbureter, taken through the center of the air intake;

Fig. 2, represents a vertical sectional view, on llne 2-2, of' Fig. 1, showing an immovable venturi.

In the preferred construction the carbureter as a whole is formed of three component parts comprisin a main section A containing the mixing 0 amber proper, and having connected thereto a throttle chamber B adapted to be secured to the intake manifold, and a liquid fuel chamber C.

In the drawings, the section A is provided with an air intake 1, provided with the usual valve 2, and also with an extension 3, in which is formed the intake to the fluid chamber. The depending extension 4 serves as a support for the shell C of the liquid fuel chamber. Within said extension is formed a chamber 5, which at its upper end is provided with a duct 6 opening into the bottom of a well 7 formed in and depressed below the floor of the mixing chamber. The duct 6 is provided with a valve seat cotiperatingwith the needle valve 8 formed on the end of the valve stem 9, which is threaded into the depending portion 4, and is adapted to be operated by any preferred form of handle 10. A suitable stufiing box 11 serves to secure a tight connection for the valve stem and prevent vibration accidentally opening the valve. A duct 12 serves to conduct the fluid in the chamber 0 to the chamber 5, from which it the duct 6 into the well 7.

The liquid fuel inlet 3 has formed therein an inlet duct 13 arranged to conduct the fluid to the'liquid fuel chamber C, said duct being controlled by valve 14 automatically operated by means of a suitable float 15. As shown, the duct 13 is formed in a suitable sleeve 16, which is tightly seated in a suitable aperture formed in the casing A. In the preferred construction, the float 15 is pivotally supported at 17 and is provided with an arm 18 which extends beneath the valve 14, loosely supporting the same. The float 15 isso ositioned as to maintain the passes upward throughlevel of the liquid fuel, in the chamber C substantially on a level with the floor of the mixing chamber, thus tending at all times to keep the well 7 filled by the action of gravity alone.

From a point near the bottom of the well '7, as clearly shown in Fig. 2, a duct 19 is formed in the wall of the casing and extends thence outward and upward to a point above the throttle valve 30 in the part B, terminating as at 20. At any preferred point an air duct 21 extends from the exterior of the device and communicates with the duct 19.

The interior of the lower part of the casing A is circular and formed with inwardly inclined walls 22. Centrally positioned within said walls is a venturi 23 normally supported in such position that its lower circular edge incloses the well 7 and is spaced above the floor of the casing. In the form herein shown, the venturi is movable in a vertical direction. It is provided with a circular shoulder 24 resting upon a coiiperating shoulder 25 formed in the casing. -As shown in the drawings, suitable pockets 26 are formed about the upper edge of the venturi, in which are positioned springs 27, at their lower ends engaging with the lower wall of the pocket and at their upper ends in contact with a suitable abutment or shoulder 28. The exterior of the upper part of the venturi movably but rather closely fits the coiiperating wall of the casing, in such manner as to allow the venturi to rise and fall a limited distance therein. Above the venturi and communicating therewith is the outlet 29 controlled by the throttle 30 carried by the oscillating shaft or stem 31. Upon one end of/the shaft is the usual stop 32, operating to control the osclllatlon of the stem in either direction, and upon the other I ting a limited supply of air therethrough in the path of the outgoing mixture.

The usual vent for the float chamber is indicated at 40. An overflow and air duct 41 extends from a point slightly above the floor of the mixing chamber to the exterior,

"incidentally serving as an additional air duct, but principally serving as an overflow to relieve the, casing from any excess of fuel which may for any reason gather therein. In the preferred construction the spring casing 34 is longitudinally slotted or grooved on one face at 42 and the strip 43 cut from the plate 37 to form the slot 39 is bent backward and is positioned in the slot 42 forming a sliding engagement between the two, serving, owever, to cause the rotation of the casing 34 to rotate the plate.

The venturi, as shown, is also spaced from the wall of the casing, thus providing a substantially annular air passage thereabout, so that as the air is admitted through the inlet 1, it passes about the venturi and beneath the same at all sides thereof.

In the construction shown in Fig. 1, the capacity of the annular air passage about the exterior -of the venturi at the point where the latter is in spaced relation to the side walls of the casing near the bottom thereof, is slightly less than the capacity or area of the bore of the venturi. As the venturi is lifted as will be described, the area between the latter and the wall of the casing at the lower edge of the venturi will be slightly increased, this actionserving as an automatic regulator of the air supply to the venturi.

As thus described, the operation of the device is substantially as follows: Assuming the throttle to be closed, on starting the engine a supply of fuel is drawn from the filled well 'I through the duct 19, which on its passage is supplied with the requisite quantity of air through the duct 21, discharging the mixture at 20 above the throttle valve 30. This is a rich starting mixture. In this action the well is constantly supplied with the requisite amount of liquid fuel by the action of gravity. After the engine is initially started, the gradual opening of the throttle serves to first gradually uncover the duct 38, admitting an additional supply-of air to the rich mixture being discharged above the throttle through the duct 19. As the throttle continues to open, the duct 38 is closed by the rotation of the plate 37. The opening of the throttle draws the air through the inlet into the annular passage or chamber, and thence beneath the lower edge of the venturi, the velocity of the passing air picking up the fuel in the well, which thereafter, as it is admitted, moves upward and is delivered with a spraying action into the assing air, serving to thoroughly co-ming e the same in the venturi. This action serves to relieve the duct 19 from further important duty at this time. As the engine speeds up, the velocity of the incoming air is increased and passing beneath the venturi, lifts the latter upward, increasing the area of the opening between the venturi and the walls 22 of the chamber for the increased volume of the air. This action automatically increases the volume of the air as compared to the volume of fuel, thus modifying the quantity of fuel admitted.

In the preferred construction, I so arrange the throttle as to permit aslight opening between the margin thereof at some point and the cooperating wall of the throttle chamber. That is, I form a slight crack at that point, which in the starting of the engine serves to permit the air or mixture within the venturi to escape at that point and mix with the incoming rich mixture through the port 20. In the drawings, 30 indicates the preferred point at which this crack occurs in relation to the valve itself.

As shown in Fig. 2, the construction is the same with the exception that the venturi 23 is immovably maintained in the mixing chamber. The upper part of the venturi has an outward extension 41, which rests upon the shoulder 25 on the casing. A sleeve 42 snugly fitting the interior of the casing rests upon the extension 41, and at its top contacts with and is securely held in place by the lower extension on the part C, resting thereon. The operation is the same except that the automatic air regulation by the vertically operating venturi is not present.

Having thus described my invention, it is obvious that various modifications may be made therein without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the particular details and form herein described further than 'as is set forth and required by the claims annexed hereto.

What I claim as new and desire to secure by Letters Patent is:

1. In adevice of the character described, a constant level chamber, a mixing chamber, the floor of said chamber being substantially at the same level as the surface of the liquid in the constant level chamber, a well formed in the floor connected at its bottom with the constant level chamber, a throttle valve in the throttle valve and an air the outletof the mixing chamber, an auxiliary duct'extending from a point adjacent the bottom of the well to a point in the outlet of the-mixing chamber sli htly beyond in ct communicatin with said auxiliary duct.

2. n a device of the character described, a oonstant'level chamber, a mixing chamber, the floor of said chamber being substantially at the same level as the surface of the liquid in the constant level chamber, a well formed in the floor connected at its bottom with the constant level chamber, a throttle valve in the outlet of the mixing chamber, a venturi tube in the mixing chamber with its lower end raised above the floor of the mixing chamber and surrounding the well and spaced from the walls of the mixing chamduct extending from a bottom of the well to a of the mixing-chamber throttle valve and an air communicating with said auxiliary point adjacent the point in the outlet slightly beyond the inlet duct.

3. In device of the character described, a constant level chamber, a mixin chamber,

the floor of said chamberbeing su stantially at the same level as the surface of the liquid in the constant level chamber, a well formed in the floor connected at its bottom with the constant level chamber, a throttle valve in the outlet of the mixing chamber and having its shaft extending through the walls of said chamber, an auxiliary valve having a port of limited size mounted on said throttle valve shaft, an auxiliary duct extending from a point adjacent the bottom of the well to a point in the mixing chamber slightly beyond the throttle valve, an air inlet communicating with said auxiliary duct, and an auxiliary air inlet opening into said mixing chamber beyond said throttle valve and controlled by said auxiliary valve so that said air inlet is opened and then closed during the initial portion of the opening movement of the throttle valve.

In testimony whereof I have hereunto signed my name in the presenceof' two subscribing witnesses.

JAJGK' W. JOHNSON. Witnesses I JOHN W. HILL, CHARLES vI. Conn. 

